Non-enzymatic Antioxidant Parameters Research Articles

ОКИСЛИТЕЛЬНО-АНТИОКСИДАНТНЫЙ СТАТУС ОРГАНИЗМА НОВОРОЖДЁННЫХ ДЕТЕЙ ПРИ СПЕЦИФИЧЕСКИХ ВНУТРИУТРОБНЫХ ИНФЕКЦИЯХ

Objective: To evaluate lipid peroxidation (LPO) and antioxidant defense (AOD) system in full-term and preterm neonates with specific intrauterine infections (IUI). Methods: Eighty full-term and preterm newborns with specific IUI were examined; 48 of them (60%) with a severe course of IUI, and 32 (40%) with an extremely severe IUI course. The control group included 30 relatively healthy newborns, including 22 full-term and 8 late premature (born at 34-37 weeks of gestation) neonates. The state of LPO and AOD was assessed by the levels of malondialdehyde (MDA), superoxide dismutase (SOD), ascorbic (AA), and sialic (SA) acids. Enzyme-linked immunosorbent assay (ELISA) of blood serum of newborns with IUI and their mothers was carried out in paired sera, with IgG, IgM, and avidity level (%) of IUI pathogens determined. Results: Analysis of epidemiological data on TORCH infection in the examined neonates revealed diagnostic titers of cytomegalovirus infection (91.3%), herpes (70.4%), toxoplasmosis (50.1%), and chlamydia (43.4%). Comparative analysis of MDA level in the first and control groups showed a statistically significant difference (p 0.05); while its comparison between the 2nd and control group showed even higher level difference (p 0.05). The levels of SOD, AA and SA in the 1st and 2nd groups were highly significantly different from the control group (p 0.001). All these tests showed significant differences between the 1st and the 2nd group (p 0.05), except for the levels of sialic acid (p 0.05). Conclusion: In neonates with specific IUI, statistically significant changes in LPO and AOD parameters were obtained compared with the control group. Enzymatic and non-enzymatic antioxidant parameters can be diagnostically significant for early prediction of infectious processes in the body of a newborn. The revealed changes in the LPO and AOD indicators in the neonates with IUI, dictate the need for timely and adequate antioxidant therapy along with etiotropic treatment. Keywords: Homeostasis, lipid peroxidation, intrauterine infections, antioxidant defense, tricarboxylic acid cycle.

MgO nanoparticles priming promoted the growth of black chickpea

Seed priming with nanoparticles (NPs) has potential to promote crop productivity and agricultural sustainability. However, detailed studies are required to find out the appropriate dose of a particular NPs required that further depends upon the type of test plant. Present study reports the influence of MgO-NPs nanopriming on black chickpea. Black chickpea treated overnight with 10–150 μg/ml NPs showed altered morphology, and variation in antioxidants, protein, and carbohydrate content. The shoot and root length were increased by 171-142 and 217–328% on MgO-NPs priming. MgO-NPs mediated increase in chlorophyll content induced 112 and 15% enhancement in the biomass and carbohydrate levels of chickpea. Further, the protein accumulation was enhanced in chickpea. Increase in carbohydrate content was found to significantly reduce the protein precipitating tannins, and thus increasing protein digestibility and solubility. MgO-NPs priming considerably increased the enzymatic and non-enzymatic antioxidant parameters of chickpea. Hence, a concentration-dependent positive response of MgO-NPs on chickpea growth and biochemical parameters was evident. This study further supports the potential of MgO-NPs as nano-fertilizers for agricultural sustainability and productivity. • Exposure to 10–150 μg/ml MgO NPs induced concentration-dependent enhancement of chickpea growth. • MgO NPs increased shoot-root length, antioxidant potential, carbohydrate, and protein content. • MgO NPs increased chlorophyll, fresh biomass, non-enzymatic and enzymatic antioxidants. • Plant response to MgO NPs needs to be investigated in other crops plants.

中华蚊母树在干旱-水淹交叉胁迫下形态和活性氧代谢的适应机制

PDF HTML阅读 XML下载 导出引用 引用提醒 中华蚊母树在干旱-水淹交叉胁迫下形态和活性氧代谢的适应机制 DOI: 10.5846/stxb202008062050 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（51779127）；国家111引智基地项目（D20015）；中国科学院水生植物与流域生态重点实验室开放课题基金（E0520204）；三峡库区珍稀植物种子保存技术与设施研究科研项目-耐水淹种质资源调查及收集（SDHZ2021346） Adaptive mechanism of morphology and reactive oxygen species metabolism of Distylium chinense seedlings to alternate drought and submergence stresses Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为阐明中华蚊母树（Distylium chinense）在消落带干旱-水淹交叉胁迫下的形态和活性氧（ROS）代谢适应机制，通过控制实验模拟了三峡水库消落带的水文节律，研究了干旱-水淹交叉胁迫及恢复过程施加不同外源物质对中华蚊母树形态学和ROS清除的变化。结果表明：（1）前期干旱胁迫增强了中华蚊母树对后期水淹胁迫的适应，主要表现在叶片脱落、大量不定根的形成及茎基部膨大等形态学的变化；（2）干旱或水淹单一胁迫下，中华蚊母树·OH、O2·等ROS水平明显高于对照，表现出氧化应激反应，其超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）等抗氧化系统酶活性及脯氨酸（Pro）等抗氧化系统小分子含量也均显著高于对照，表现出一定的抗氧化防御作用机制，且在复合胁迫下，SOD、CAT、APX酶活性及Pro含量显著高于单一胁迫；（3）恢复阶段，相关性分析表明，中华蚊母树清除ROS （·OH、O2·）的酶促（SOD、CAT、APX）及非酶促（Pro）系统具有一定的协同性。同时，恢复阶段施加脱落酸（ABA），内源Pro显著高于正常水平；施加Pro，SOD、CAT等抗氧化酶活性显著高于对照；施加可溶性糖（Glu），APX活性显著升高。表明外源添加ABA、Pro、Glu，均对ROS的清除产生显著影响，同时，SOD活性显著高于CAT和APX活性，因此SOD可能是中华蚊母树清除冗余ROS的主要因子。因此，中华蚊母树形态学的变化、较高的脯氨酸积累和对ROS有效的清除防御，可能是其适应干旱-水淹交叉胁迫的主要机制，ABA、Pro、Glu等外源物质的添加对中华蚊母树的胁迫恢复过程具有显著的促进作用，前期干旱可提高中华蚊母树植株对后期水淹的耐受能力。 Abstract:Distylium chinense, the genus Distylium of the Hamamelidacea, is an evergreen perennial shrub between 0.8 and 1.2 m in height, native to the riparian areas and wetlands and a dominant species in the riparian areas of the Three Gorges Reservoir (TGR) region of the Yangtze River and its branches. Our previous studies showed that D. chinense had a certain survival rate in the middle and upper part of the water level fluctuation zone (WLFZ) of the TGR to alternate drought and submergence stresses, but the adaptive mechanisms of its morphology and reactive oxygen species (ROS) metabolism is still unknown. To evaluate its adaptation mechanisms of D. chinense to alternate drought and submergence stresses, a simulation alternate drought and submergence experiment was conducted, and morphology and ROS metabolism of D. chinense seedlings and their recovery growth with different exogenous substances, i.e., abscisic acid(ABA), proline(Pro) and glucose (Glu), were analyzed, including adventitious roots, plant height, base stem diameter, leaf numbers, ROS content, enzymatic and non-enzymatic antioxidant parameters. The results were as follows. (1) The early drought stress stimulated the adaptation of D. chinense seedlings to the later flooding stress.The adaptation mainly refered as more morphological changes of stems and roots i.e., stem base hypertrophy, formation and development of adventitious roots. (2) Comparing to the control group, there were significant increases in the ·OH and the O2· in D. chinense seedlings under either drought or flooding stress, which showed oxidative stress responses occurred and their superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT) activities and the proline (Pro) contents were also significantly higher than those of controls, which showed that the enzymatic and non-enzymatic antioxidants were induced as a defense mechanism. Under the alternate drought and submergence stresses, the activities of SOD, APX and CAT and Pro contents were higher than those under single drought or flooding stress. (3) Correlation analysis showed that to a certain extent there were coordinated effects between the enzymatic (SOD, CAT, APX) and non-enzymatic (Pro) systems in ROS-scavenging in D. chinense. Exogenous ABA significantly triggered an increase of endogenous Pro contents compared to the controls during the recovery growth and the activity of SOD, CAT and APX was significantly higher than those of the control group under exogenous Pro treatment. Of these, the activities of SOD were significantly higher than those of CAT and APX. The activities of APX increased significantly when soluble sugar (Glu) was added. The ABA, Pro and Glu all had significant influences on the removal of ROS and the ability of D. chinense to up-regulate the SOD activity might be an important attribute for the removal of redundant ROS linked to drought and flooding tolerance. Thus the higher Pro accumulation and effective defense to ROS could be the main physiological adaptation mechanisms for D. chinense under the alternate drought and submergence stresses. The combination of morphological changes and the up-regulating of enzymatic and non-enzymatic anti-oxidative system might be the main mechanisms of D. chinense adapting to alternate drought and flooding stresses. The ABA, Pro and Glu treatment significantly promoted the recovery growth of D. chinense.. The drought in the early stage could improve the tolerance to submergence in the later stage. 参考文献 相似文献 引证文献

The Impact Of Foliar Salicylic Acid In Salt-Exposed Guava (Psidium Guajava L.) Seedlings

ABSTRACT The rising demand for guava fruit worldwide is due to its richness in vitamin C, high yielding and two bearing seasons. Given the salt stress threat to guavas and the necessity of protective strategies, in the present research guava seedlings were subjected to sodium chloride (0 and 50 mM) and salicylic acid (0 and 1 mM). To ascertain a logical conclusion, the activity of antioxidant enzymes, antioxidant capacity of DPPH, ferric reducing antioxidant power, total flavonoid and phenol contents were monitored in salt-exposed guava seedlings. Based on our findings, the most superoxide dismutase (87.46 µmol min−1g−1DW) activity, ferric reducing antioxidant power (408.82 mmol g−1 DW), DPPH scavenging activity (80.65%), flavonoid (14.15 mg QE−1 g DW) and phenol (34.02 mg GAE g−1 DW) contents were found in 50 mM NaCl-exposed plants, which were enriched by 1 mM salicylic acid. A high correlation was observed among non-enzymatic antioxidant parameters (DPPH scavenging activity, ferric reducing antioxidant power, total flavonoid content and total phenol content). In conclusion, salicylic acid improved guavas salt tolerance by increasing both enzymatic (peroxidase and superoxide dismutase) and non-enzymatic (ferric reducing antioxidant power, DPPH scavenging activity, total phenol and flavonoid contents) pathways.

Stage-dependent concomitant microbial fortification improves soil nutrient status, plant growth, antioxidative defense system and gene expression in rice

Stage-dependent concomitant fortification of rice (Oryza sativa L.) varieties PB1612 and CO51 with microbial inoculants Trichoderma asperellum and Pseudomonas fluorescens as seed coating, seedling root inoculation and soil application enhanced growth, activated antioxidant enzymes and modulated defence-related genes in plants. Microbial inoculants improved shoot height, tiller numbers, fresh weight and dry biomass. Co-inoculation was more impactful in enhancing plant growth and development as compared to single inoculation. Single and co-inoculation improved organic carbon (OC) and N, P and K content in the soil substantially. Mean values between control and co-inoculation varied significantly for OC in PB1612 (p0.001) and CO51 (p0.019) and phosphorus content in PB1612 (p0.044) and CO51 (p0.021). Microbial inoculation enhanced soil nutrients and increased their bioavailability for the plants. Total polyphenolics, flavonoids and protein content increased in the leaves following microbial inoculation. Enhanced non-enzymatic antioxidant parameters (ABTS, DPPH, Fe-ion reducing power and Fe-ion chelation) was found in microbe inoculated rice reflecting high free radical scavenging activity in polyphenolics-rich leaf extracts. Increased enzyme activity of superoxide dismutase (SOD), glutathione reductase (GR), phenylalanine ammonia-lyase (PAL), peroxidase (PO), glutathione peroxidase (GPX), ascorbate peroxidase (APX) and catalase (CAT) showed improved ROS scavenging in rice plants having co-inoculation. Over-expression of PAL, cCuZn-SOD and CAT genes in microbial inoculated rice plants was recorded. The study concludes that plant stage-wise concomitant fortification by microbial inoculants could play multi-pronged manifestations at physiological, biochemical and molecular level in rice to positively influence growth, development and defense attributes in plants.

Whole-Body Cryotherapy Decreases the Levels of Inflammatory, Oxidative Stress, and Atherosclerosis Plaque Markers in Male Patients with Active-Phase Ankylosing Spondylitis in the Absence of Classical Cardiovascular Risk Factors

Objective The aim of the study was to estimate the impact of whole-body cryotherapy (WBC) on cardiovascular risk factors in patients with ankylosing spondylitis (AS). Material and Methods We investigated the effect of WBC with subsequent kinesiotherapy on markers of inflammation, oxidative stress, lipid profile, and atherosclerosis plaque in male AS patients (WBC group). To assess the disease activity, the BASDAI and BASFI were also calculated. The results from the WBC group were compared with results from the kinesiotherapy (KT) group. Results The results showed that in the WBC group, the plasma hsCRP level decreased without change to the IL-6 level. The ICAM-1 level showed a decreasing tendency. The CER concentration, as well as the BASDAI and BASFI, decreased in both groups, but the index changes of disease activity were higher in the WBC than KT patients. Additionally, in the WBC group, we observed a decrease in oxidative stress markers, changes in the activity of some antioxidant enzymes and nonenzymatic antioxidant parameters. In both groups, the total cholesterol and LDL cholesterol, triglycerides, sCD40L, PAPP-A, and PLGF levels decreased, but the parameter changes were higher in the WBC group. Conclusion WBC appears to be a useful method of atherosclerosis prevention in AS patients.

Effect of heavy metals on tissue-specific antioxidant response in Indian major carps.

Concentrations of heavy metals (Cu, Ni, Zn, Cd and Pb) were measured in sediments, water and liver and kidney tissues of three Indian major carps (Labeo rohita, Catla catla and Cirrhinus cirrhosus), belonging to two different weight groups (250 and 500g), collected from ponds at two different sites (Nalban bheri and Diamond Harbour). The tissues were analysed for the levels of different antioxidant defence systems such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GRd), glutathione S-transferase (GST), glutathione (GSH) and malondialdehyde (MDA). Concentrations of all the metals were significantly higher (P<0.05) in sediment, water and the tissues from Nalban bheri compared to those in Diamond Harbour. Metal concentrations were the lowest in C. cirrhosus, which increased with an increase in fish weight, and the liver accumulated higher amount of metals than the kidney. Activities of all enzymatic and non-enzymatic antioxidant parameters except GPx and GRd were significantly higher (P<0.05) in the tissues from Nalban bheri than those in Diamond Harbour. Significant multicollinearity was found in the values of SOD, CAT, GST, GRd, GPx and MDA with Pb, Cu and Ni in all three fish species at Nalban and with Cd in L. rohita and C. catla. Principal component analysis results revealed that stress response in a polluted site was directly regulated by an amalgamation of GSH profile and the levels of MDA in a synchronized manner. The study indicated a tissue-specific and species-specific difference for heavy metal-induced oxidative stress response in fish and a correlation between different heavy metals and individual oxidative stress markers.

Oral administration of Nigella sativa oil ameliorates the effect of cisplatin on brush border membrane enzymes, carbohydrate metabolism and antioxidant system in rat intestine

Cisplatin (CP) is an effective chemotherapeutic agent that induces gastrointestinal toxicity. Nigella sativa oil (NSO) has been shown to be beneficial in a wide range of gastrointestinal disorders. The present study investigates the possible protective effect of NSO on CP-induced gastrointestinal toxicity. NSO administration (2ml/kg bwt, orally), prior to and following, a single dose CP treatment (6mg/kg bwt. ip), significantly attenuated the CP-induced decrease in brush border membrane (BBM) enzyme activities in intestinal homogenates and BBM vesicles (BBMV). NSO administration also mitigated CP induced alterations in the activities of carbohydrate metabolism enzymes and in the enzymatic and non-enzymatic antioxidant parameters in the intestine. The results suggest that NSO by empowering the endogenous antioxidant system improves intestinal redox and metabolic status and restores BBM integrity in CP treated rats. Histopathological studies supported the biochemical findings. Thus, NSO may help prevent the accompanying gastrointestinal dysfunction in CP chemotherapy.

Fish Oil Supplementation Ameliorates Long Term Cisplatin Treatment Induced Toxicity and Oxidative Damage in Rat Kidney

Background: Cisplatin (CP) is an effective chemotherapeutic agent widely used against various malignancies. However, CP exerts several side effects through oxidative stress by generating reactive oxygen species (ROS). The major side effect of CP chemotherapy is dose dependent nephrotoxicity that limits its clinical usage. We have previously shown that fish oil (FO) supplementation ameliorated gentamicin induced nephrotoxicity as evident by increase in the activities of brush border membrane (BBM) and free radical scavenging enzymes in rat kidney. In the present study we aimed to investigate whether fish oil (FO) can prevent the long term CP-induced nephrotoxic effects. Methods: Rats were divided into four groups viz. control, CP, CPF and FO alone group. Rats in the groups CPF and FO were fed experimental diet prior to and simultaneously with or without CP treatment (3 mg/kg bwt i.p) respectively. Results: FO supplementation to CP treated significantly mitigated the CP induced increase in serum creatinine (Scr) and blood urea nitrogen (BUN) and decrease in the activities of brush border membrane (BBM) enzymes in renal cortical and medullary homogenates as well as in isolated BBM vesicles (BBMV). FO consumption also reduced CP induced alterations in the activities of carbohydrate metabolism enzymes and in the enzymatic and non-enzymatic antioxidant parameters. Conclusion: These results suggest that FO have potential to abrogate CP induced nephrotoxicity and can be a useful adjuvant in long term CP chemotherapy without any side effects. Moreover, the inherent anti-cancer properties of FO with CP treatment may exhibits synergistic beneficial effects.

Protective effect of Nigella sativa oil on cisplatin induced nephrotoxicity and oxidative damage in rat kidney

BackgroundNephrotoxicity is a severe complication in patients undergoing cisplatin (CP) chemotherapy. Previous studies in our lab have shown that administration of a single dose of CP results in decrease in the activities of brush border membrane (BBM) and free radical scavenging enzymes and induces oxidative stress in rat kidney. Nigella sativa, is one of the most revered medicinal plant known for its numerous health benefits. Nigella sativa seed/oil has been shown to improve kidney functions in animal models of acute kidney injury. ObjectiveThe present study was undertaken to investigate whether Nigella sativa oil (NSO) can prevent the CP-induced nephrotoxic effects. ResultsThe effect of NSO was determined on CP induced alterations in various serum parameters and on enzymes of carbohydrate metabolism, BBM and antioxidant defense system in renal cortex and medulla. Administration of NSO (2ml/kg bwt. orally), prior to and following a single dose CP treatment (6mg/kg bwt. i.p), significantly attenuated the CP induced increase in serum creatinine (Scr) and blood urea nitrogen (BUN) and decrease in the activities of BBM enzymes in renal cortical and medullary homogenates as well as in isolated BBM vesicles (BBMV). NSO administration also precluded CP induced alterations in the activities of carbohydrate metabolism enzymes and in the enzymatic and non-enzymatic antioxidant parameters. Histopathological observations showed extensive kidney damage in CP treated animals and remarkably reduced renal injury in CP and NSO co-treated group. ConclusionThe biochemical and histological data suggest a protective effect of NSO against CP-induced acute kidney injury.

Antihypercholesterolemic and antioxidative effects of an extract of the oyster mushroom, Pleurotus ostreatus, and its major constituent, chrysin, in Triton WR-1339-induced hypercholesterolemic rats

Hypercholesterolemia and oxidative stress are known to accelerate coronary artery disease and progression of atherosclerotic lesions. In the present study, an attempt was made to evaluate the putative antihypercholesterolemic and antioxidative effects of an ethanolic extract of the oyster mushroom (Pleurotus ostreatus) and chrysin, one of its major components, in hypercholesterolemic rats. Hypercholesterolemia was induced in rats by a single intraperitoneal injection of Triton WR-1339 (300 mg/kg body weight (b.wt.)), which resulted in persistently elevated blood/serum levels of glucose, lipid profile parameters (total cholesterol, triglycerides, low-density lipoprotein-, and very low-density lipoprotein-cholesterol), and of hepatic marker enzymes (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase). In addition, lowered mean activities of hepatic antioxidant enzymes (catalase, superoxide dismutase, and glutathione peroxidase) and lowered mean levels of nonenzymatic antioxidants (reduced glutathione, vitamin C, and vitamin E) were observed. Oral administration of the mushroom extract (500 mg/kg b.wt.) and chrysin (200 mg/kg b.wt.) to hypercholesterolemic rats for 7 days resulted in a significant decrease in mean blood/serum levels of glucose, lipid profile parameters, and hepatic marker enzymes and a concomitant increase in enzymatic and nonenzymatic antioxidant parameters. The hypercholesterolemia-ameliorating effect was more pronounced in chrysin-treated rats than in extract-treated rats, being almost as effective as that of the standard lipid-lowering drug, lovastatin (10 mg/kg b.wt.). These results suggest that chrysin, a major component of the oyster mushroom extract, may protect against the hypercholesterolemia and elevated serum hepatic marker enzyme levels induced in rats injected with Triton WR-1339.

Influence ofAlternanthera brasiliana(L.) Kuntze on Altered Antioxidant Enzyme Profile during Cutaneous Wound Healing in Immunocompromised Rats

Alternanthera brasiliana (L.) Kuntze (Amaranthaceae) is a herbaceous plant used against inflammation, cough, and diarrhea in Brazilian popular medicine. In our preliminary study, promising wound healing activity of methanol extract of leaves of A. brasiliana (MEAB) was observed in normal excision and incision wound models. Therefore, the present study was designed to investigate the wound healing activity along with the antioxidant enzyme profile during cutaneous excision immunocompromised wound after topical application of 5% w/w ointment of MEAB in rats. Immunocompromised state was induced by pretreatment with hydrocortisone (HC) at 40 mg/kg body weight (i.m.) in male rats. Following one-week pretreatment with HC, wounds were created. The vehicle, 5% (w/w) ointment of MEAB, or standard drug (Himax) was applied topically twice daily. Healing potential was evaluated by the rate of wound contraction, estimation of enzymatic and nonenzymatic antioxidants like catalase, SOD, GSH, protein, vitamin C, and hydroxyproline content, which was supported by histopathological study on the 8th day following wounding. There was significant increase in the enzymatic and nonenzymatic antioxidant parameters in the extract-reated group as compared to control group. Histopathological study revealed collagen deposition, fibroblast proliferation, angiogenesis, and development of basement membrane in A. brasiliana group. The results of the present investigation revealed significant wound healing activity of MEAB.

Effect of topical application of fluoride gel NaF 2% on enzymatic and non-enzymatic antioxidant parameters of saliva

ObjectiveThe aim of the study was to evaluate the effect of topical fluoride gel NaF 2% application on antioxidant parameters of whole saliva from children. DesignThe saliva mechanically stimulated with parafilm was collected from 25 children (6–12 years) attending the Clinic of Paediatric Dentistry of Universidade Cruzeiro do Sul, São Paulo, Brazil, before (control group) and immediately after application of neutral fluoride gel NaF 2% (fluoride-gel group), according to the Standards for Research Using Human Subjects, Resolution 196/96 of the USA National Health Council of 10/10/1996. Afterwards, pre-post ferric-reducing antioxidant power (FRAP), trolox-equivalent antioxidant capacity (TEAC), uric acid, reduced/oxidised glutathione content (GSH/GSSG) and total peroxidase activity (TPO) were evaluated in whole saliva of both groups. ResultsAll non-enzymatic antioxidant parameters were augmented by fluoride-gel NaF 2% application, whereas a notable reduction (31%) of peroxidase activity was concomitantly observed in the children's saliva (p≤0.05). Nevertheless, the reducing power of saliva was kept unaltered under these circumstances (p≤0.05). ConclusionsDespite the reduced activity of peroxidase (an important antimicrobial and antioxidant enzyme), the topical fluoride gel NaF 2% favourably stimulated the release of non-enzymatic antioxidant components of saliva, sustaining the reducing power of saliva and the natural defences of the oral cavity.

Status of lipid peroxidation, glutathione, ascorbic acid, vitamin E and antioxidant enzymes in patients with osteoarthritis

The exact pro-oxidant and antioxidant status in osteoarthritis patients is still not clear. To add a new insight to the question, changes in the erythrocyte lipid peroxidation products (MDA), levels of glutathione (GSH), ascorbic acid and plasma vitamin E (nonenzymatic antioxidant parameters); and activities of antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPX), catalase in erythrocytes and plasma glutathione - S - transferase (GST) were measured in patients with osteoarthritis. This work was undertaken to assess oxidative stress and antioxidant status in patients with osteoarthritis. The study was conducted in 20 patients and compared to controls. Levels of erythrocyte MDA, GSH, ascorbic acid, plasma vitamin E; and activities of antioxidant enzymes were measured in patients with osteoarthritis. Erythrocyte GSH was measured by the method of Beutler et al. Ascorbic acid levels were measured by the method of Tietz. Plasma vitamin E levels were measured by the method of Baker et al. MDA was determined as the measure of thio barbituric acid reactive substances (TBARS). SOD activity in the hemolysate was measured by the method of Misra and Fridovich. Activity of catalase was measured by the method of Beers and Sizer. GPX activity was measured as described by Paglia and Valentine in erythrocytes and Plasma GST activity was measured as described by Warholm et al. These parameters were measured in 20 patients and compared to controls. Statistical analysis between group 1 (controls) and group 2 (patients) was performed by the student's t - test using the stat -view package. It was observed that there was a significant increase in erythrocyte MDA levels; SOD, GPX and plasma GST activities; and a significant decrease in erythrocyte GSH, ascorbic acid, plasma vitamin E levels and catalase activity in patients with osteoarthritis when compared to controls. The results of our study suggest higher oxygen-free radical production, evidenced by increased MDA and decreased GSH, ascorbic acid, vitamin E and catalase activity, support to the oxidative stress in osteoarthritis. The increased activities of antioxidant enzymes may be a compensatory regulation in response to increased oxidative stress.

POTENTIAL PROTECTIVE EFFECT OF MELATONIN AGAINST DIBROMOACETONITRILE-INDUCED OXIDATIVE STRESS IN MOUSE STOMACH

Dibromoacetonitrile (DBAN) is a disinfection by-product following chlorination of drinking water. Epidemiological studies indicate that it might present a potential hazard to human health. DBAN was previously found to induce oxidative stress in rat stomach as manifested by perturbation of some enzymatic and nonenzymatic antioxidant parameters. Therefore, we have investigated the oxidative stress possibly induced by DBAN in mouse stomach and possible protection by melatonin (MLT) as a free radical scavenger. In a dose-response study, mice were administered a single oral dose of DBAN (30, 60 and 120 mg kg −1) and were sacrificed after 1 h. DBAN significantly reduced glutathione (GSH) content that was somehow dose-related, and inhibited glutathione- S-transferase (GST) activity in gastric tissues. The highest dose of DBAN (120 mg kg −1) lowered GSH by 74% and induced a significant elevation of lipid peroxidation products, determined as thiobarbituric acid reactive substances (TBARS) by 69%. The same dose inhibited the gastric activities of GST, superoxide dismutase (SOD) and catalase (CAT) by 70, 57 and 23%, respectively. In a time-course study, mice were administered DBAN (60 mg kg −1 p.o.) and sacrificed 0.5, 1, 3, 6, 12 and 24 h after treatment. GSH was dramatically depleted at 0.5, 1, 3 and 6 h (45, 38, 39 and 49% of control, respectively) and remained significantly low at 12 and 24 h. Also, DBAN caused an accumulation of TBARS in gastric tissues starting from 3 h and was maximum at 6 h (133% of the control). The enzymatic activities of GST and SOD were maximally inhibited by DBAN treatment at 0.5 h (32% for GST and 37% for SOD of the respective control). The activities of both enzymes returned to control values at 24 h. CAT activity was not affected by DBAN administration at all. Pretreatment of another group of mice with melatonin (10 mg kg −1 per day p.o. 12 days) before administration of DBAN (60 mg kg −1 p.o.) completely mitigated the aforementioned parameters. In conclusion, the present study indicates that DBAN induces a marked oxidative stress in mouse stomach as evidenced by GSH depletion, TBARS accumulation and GST, SOD and CAT inhibition. Melatonin could mitigate DBAN-induced oxidative stress in mouse stomach as it did almost normalize both the enzymatic and nonenzymatic antioxidant parameters.

ANTIOXIDANT STATUS AND LIPID PEROXIDATION IN COLORECTAL CANCER

Colon carcinogenesis is a multistep process where oxygen radicals were found to enhance carcinogenesis at all stages: initiation, promotion, and progression. Since insufficient capacity of protective antioxidant system can result in cancer, the aim of this study was to examine the activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) and the levels of reduced glutathione, vitamin C, and vitamin E. The lipid peroxidation products were also determined by measuring malondialdehyde and 4-hydroxynonenal levels in colorectal cancer tissue collected from 55 patients. In these cases the activity of superoxide dismutase, glutathione peroxidase, and glutathione reductase was significantly increased while the activity of catalase was significantly decreased in cancer tissue. However, the level of nonenzymatic antioxidant parameters (glutathione, vitamin C, and vitamin E) was significantly decreased in cancer tissue. Further lipid peroxidation was enhanced during cancer development, manifested by a significant increase in malondialdehyde and 4- hydroxynonenal levels. The obtained results indicate significant changes in antioxidant capacity of colorectal cancer tissues, which lead to enhanced action of oxygen radicals, resulting in lipid peroxidation.